Perhaps "Notation as a Tool of Thought" - http://www.jsoftware.com/papers/tot.htm - could help you, if you want to understand why people keep writing APL and its successors? Like Mathematica, for example?..

Do you think mathematical articles are understandable and maintainable?

What if there is not a lone J genius, but a whole - small - department of people, who spend time actually thinking and talking about computations, not the ways to express it?